Synthesis of hydrocarbons



April 11, 195o J. H. GRAHAME SYNTHESIS oF HYnRocARBoNs 2 Sheets-Sheet 1 Filed April 41.6, 1947 INVENTOR. uffi/w55 Hfg ATTORNEY April 1l, 1950 J. H. GRAHAME l SYNTHESIS oF'HYDRocARBONs 2 Sheets-Sheet 2 Filed April 16, 1947 INVENToR JA ESHGPAHAME Patented` Apr. l1, 1950 SYNTHESIS F HYDROCABBONS Jamel H. Grahame, Mount Vernon, N. Y., as-

slgnor to Texaco Development Corporation, New York, N. Y., a corporation oi' Delaware Application April 18, 1947, Serial No. 741,867

The present invention is concerned with the production of hydrocarbons, oxygenated, hydrocarbons, and the like by the catalytic reduction of carbon monoxide with hydrogen, and more speciilcally involves the correlated and predetermined production and use of inevitable accompanying gaseous products of reaction, to improve and supplement the production of liquid hydrocarbons. particularly those boiling in the motor gasoline boiling range.

In accordance with the present invention, hydrogen and carbon monoxide are converted catalytically in a primary reaction zone in which operating conditions are directed for the production of branched chain aliphatic hydrocarbons together with relatively large amounts of byproduct carbon dioxide. Normally liquid fractions are recovered as a product stream and the residual gases, such as carbon dioxide and unreacted hydrogen, are supplied to a secondary synthesis reaction zone where they are mixed with additional hydrogen and carbon monoxide and catalytically treated under typical reaction conditions adapted to vproduce predominantly liquid hydrocarbons largely or essentially of oleflnlc character. Gaseous oleflns accompanying the reaction product, together with isobutane and if desired isopentane from the first reaction zone are submitted to alkylation for the production of a high quality motor gasoline fraction.

Typical processes for the synthesis of hydrocarbons currently proposed, involve passage of a synthesis gas comprising hydrogen and carbon monoxide in contact with a synthesis catalyst at elevated temperature and usually at elevated pressure with recovery of the desired hydrocarbons from the gasiform reaction products. The usual process employs a catalyst comprising a metal of the iron group or ruthenium, together with small additions of an activator and promoter such as oxides of alkali metal or alkaline earth metals, titanium, zirconium, thorium, alumina and many others. Temperatures vary with the specific catalyst selected and are usually about 400 F. or above in the case of the cobalt catalyst.

Many advantages, however result from the use of an iron catalyst preferably in a condition of iluidization and at temperatures from about 550 to 700 F., preferably about 600 F. and under an elevated pressure from 150 to 300 pounds per square inch gauge. The products tend to be oleflnic in character and thus the appropriate fractions .provide a good motor gasoline fuel.

On the other hand, it is possible to carry out ;he catalytic reduction of carbon monoxide and 9 Claims. (Cl. zml-449.6)

hydrogen for the production largely or essentially, of isoparaillns.

This isoparaiiln synthesis process employs alpparatus which is generally equivalent to that usually employed in the rst mentioned process and depends upon the action of somewhat different catalysts which have a specific selective action in promoting the formation of the aforementioned isoparaflins. Typical isoparailin synthesis catalysts are a composite alumina-thoria catalyst or a zinc oxide-alumina catalyst, which are operable usually under characteristic elevated temperatures in the range of about '150- 900 F. or more specifically in the range of about 785 F. to 840 F. Operating pressure is usually substantial, usually in the range of from 50 to 500 atmospheres, and preferably about 300 to 500 atmospheres.

The present invention, however, is not concerned, per se, with the specific catalyst or reaction conditions, and contemplates all equivalent catalystsactively eiective to promote the selective formation of isoparalns when operating under appropriate reaction conditions.

The isoparaiiin synthesis process normally results in the production of relatively large amounts of by-product carbon dioxide with corresponding loss of yield of hydrocarbons on the basis of carbon. supplied to the system. Substantial formation of carbon dioxide is moreover accomplished with a relatively low consumption of hydrogen.

In accordance with the present invention prodduct gases from the primary reaction zone, particularly the by-product carbon dioxide and hydrogen, are supplied to the secondary .reaction zone, together with the fresh feed synthesis gas therein reacted, to control the reaction and effect a desirable consumption of these constituents in the formation of additional hydrocarbon product.

The invention has the valuable advantage of permitting the direct production of isoparaiilns without the disadvantage of excessive loss of feed carbon to carbon dioxide. This follows because asoma;

to this co-pending application for all details of the process in question.

The invention has the further advantage of providing a correlated feed of isoparaiilns and olefins containing four carbon atoms or thereabout, suitable for an alkylation charge stock. The normally liquid products of reaction are usually accompanied by such fractions in quite substantial excess of over the amount which may be used to pressure the motor gasoline fractions; that is. which may be included in the commercial motor gasoline product as a desirable component, contributing to volatility, and anti-knock properties, and correspondingly swelling the volume production. The present invention segregates normal butane for this purpose, whereby C4 hydrocarbons suitable for alkylation, are so utilized, and only the normal butane becomes a blending agent in the product` gasoline. Additionally, the return of normal light gaseous hydrocarbons selectively to the synthesis reaction zone or zones in substantial quantity tends to restrict and suppress net formation thereof to usable quantities.

In order to more clearly describe the invention with reference to one specific embodiment thereof, reference is had to the accompanying drawing wherein Figure 1 represents more or less diagrammatically one preferred arrangement, and Figure 2 discloses an alternative preferred process.

Referring to Figure 1 of the drawing, the numeral I designates an inlet line supplying a fresh feed synthesis gas from any suitable source, not shown, and comprising essentially hydrogen and carbon monoxide in suitable relative proportions. This stream passes into a header il where it is`split, the upper flow passing by Way of a pump l2, and a. branch pipe i3 to the lower portion or inlet of a primary reaction zone designated by the numeral i4.

The reaction zone i4 has been designated only symbolically because of the wide variety of conventional forms it may take. Most advantageously. operation is carried out with an upstanding tubular reactor in which an isoparafiin synthesis catalyst is held in the form of a powder maintained in a state of dense phase fluidization by the upflowing reactants. Temperature control may be maintained by means of suitable cooling surfaces immersed in the catalyst mass in the usual manner and held by means of a, suitable coolant at an appropriate temperature level.

The eiiluent gasiform reaction products, after appropriate contact with the catalyst emanate from the upper pseudo-liquid level of the fluidized mass and pass through illter I5 or any other suitable separator of the cyclone, electrostatic or other type through outlet conduit IB. Throttle valve l1 in conduit I6 permits pressure reduction from the high pressures prevailing in the reaction zone I4. The products, at a lower preselected pressure, as for example 200 pounds per square inch, pass through condenser i8 to separator I9 from which condensed water vapor is removed as at 2li and normally liquid hydrocarbon fractionsy tion with a stream of suitable lean oil from pipe 2l. The downtlow of lean oil absorbs C4 hydrocarbons and is ultimately withdrawn as at 29 to stripping tower 30 from which the stripped hydrocarbon gases pass overhead as at 3i, and the stripped lean oil is returned to pipe 2l by pump I2.

Additional C4 hydrocarbons are recovered from stabilizer 34 which receivesthe normally liquid fraction of pipe 2| aforementioned and delivers the C4 fractions thereof through overhead pipe 35. The residue discharged to 36 comprises the higher hydrocarbons and any included normally liquid oxygenated hydrocarbons which may be subjected to any desired further treatment or use.

The light hydrocarbons rich in isoparaiiins in conduit 3| are combined with those in conduit 35 and pass to a fractionation tower 38 from which a separation is made between normal paraflins discharged as at 39, and an overhead of essentially light isoparallins, together with any contained oleflns discharged as at 40. Pipe 40 leads to an alkylation system to be hereinafter referred to in greater detail.

The off gases or overhead from the absorption tower 21 comprising essentially carbon dioxide, light hydrocarbon gases, and unreacted carbon monoxide and hydrogen, pass through pipe or conduit 43 to a carbon dioxide recovery system, including an absorption tower 45 and a stripper 46. 'I'his gas recovery unit, the details of which form, per se, no part of the present invention, may comprise any conventional means for the separation of carbon dioxide, such as the Girbotol system wherein an absorbent such as triethanolamine passes downwardly through the absorption tower, is removed as at 41, stripped of carbon dioxide in the tower 46, and returned to the absorption tower by way of pump 48 and conduit 49. Separated carbon dioxide comes overhead by way of pipe 5U.

The remainder of the synthesis gas in the header Il passes into secondary reactor 5| operating for the production of largely and predominantly olefin hydrocarbons. The form and arrangement of this reaction zone may be substantially identical with that disclosed in connection with the primary reactor I4 or alternatively it may take the form of any other conventional hydrocarbon synthesis reactor. Herein the fresh synthesis gas is passed, for example, upwardly through a fluidized mass of catalyst in the secondary reactor, at an elevated pressure and temperature, and the reaction products are withdrawn through conduit 52 to condenser 53 and separator 54.

Attention is particularly directed to the fact that the recovered carbon dioxide from pipe 50 is directed through branch pipe 56 to the inlet of the reactor 5I as a supplementary feed. So also it is particularly important to note that valved conduit 58 connects the aforementioned pipe 43 and pipe 56 so that stripped, normally gaseous reaction products from the primary or isoparailin synthesis step can be included in the pipe 56 stream to the secondary reactor in any desired proportion. Obviously this affords a convenient means for adjusting the total feed to the last named reactor to the desired relative proportion of carbon dioxide; hydrogen, gaseous hydrocarbons, and the like, so that the reaction occurs under conditions favorable to the desired utilization of hydrogen and carbon dioxide in the formation of olefinic type liquid hydrocarbons, and the Iless than about 1:1.

maximum suppression of light hydrocarbon gas formation.

l tained isoparamns, if any, to the alkylation unit I2 through pipe Additional alkylation stock is obtained from the gaseous overhead of separator 54 withdrawn through pipe to an absorption system identical with that used to treat the normally gaseous products from the primary. reactor and comprising an absorber Il and a stripper l2. The fractions stripped from the adsorbent liquid cornprise suitable olefin alkylation stock, preferably butylenes. These are intermingled with the product of pipe Il and treated to remove normal parailins in the fraction system 8l, previously referred to.

Stripped gas from the absorber 1I is discharged through pipe 1I for further treatment, recovery or use as fuel, or conversion to additional synthesis gas as may be desired.

Suitably valved branch pipe 14 connects pipe 'I0 and header Il to permit recycle of wet products of reaction to the reactor 5I as desired.

From the foregoing, it will be apparent that in the present process, coordinated reactors, operate respectivelyfor the production of isoparaiilnic and oleflnic hydrocarbons from which liquid hydrocarbon fractions are recovered, and the normally gaseous isoparailins and olefins are supplied in predetermined proportion to an alkylation system 42 supplying alkylate as at 80.

The invention particularly contemplates operation of the oleiln forming synthesis step under conditions adapted to result in appropriate utilization of excess carbon dioxide as previously mentioned. While approach to this desirable condition is ailorded simply by supplying the available streams of carbon dioxide and hydrogen to the reactor, the desired condition may be controllably effected by correlating the various feed streams to the reactor il as disclosed in aforementioned copending application Serial No. 630,521, so that the composition of the total feed meets the conditions speciiled therein and to which reference is hereby made.

Essentially however the total feed to the reactor is adjusted so that the molar ratio of the H to CO is 2:1 or preferably greater and the pnoportion of CO2 is raised to a value where the desired suppression or consumption of CO2 occurs. Preferably the total molar proportion of Hr is not greater than the sum of twice the molar proportion of CO plus three times the molar proportion of C02 in the total feed. Formularized, this means that the ratio of H2 to 2CO plus 3002 is Advantageously it is not below about 0.6:1.

In addition for net carbon dioxide consumption in the secondary reaction zone, it is contemplated maintaining the molar ratio:

gozan-200A) Coxlpo action at the temperature prevailing in that reaction zone, where:

A is the fraction of the carbon monoxide which will be converted in that stage. Such fraction may range from 0.90 to 0.995 for example. The equilibrium constant K for the water gas shift reaction can be expressed as:

where:

e is the base of N aperian logarithms e. g. 2.7183. and T is the reaction temperature in degrees F. The value of K ranges from 70 for a reaction temperature of about 500 F. to a value of about 16 for a reaction temperature of about '100 F. and is about 31 for a reaction temperature of about 600 F.

In general the magnitude of the net consumption of carbon dioxide increases with the excess of the above molar ratio, over the value of K.

Under these conditions, it is possible to consume all or substantial portions of the carbon dioxide available.

It is to be understood that the specific absorption fractionation and stabilizing arrangements disclosed may be substituted by any equivalent means` capable of producing an equivalent separation. Moreover, the invention fully contemplates the treatment of equivalent streams in a suitable common separation system. For example, the wet product gases from the separators i9 and 54 may be treated by common absorption or fractionation means, and similarly the respective liquid streams therefrom may be stabilized in a single stabilizing means, the combined alkylation charge stock passing in admixture to the alkylation unit.

In addition, the invention contemplates the recovery of olei'ins by absorption in a suitable acid stream forming a part of the alkylation system. For example, any suitable olefinic fraction from the secondary reaction zone may be passed into a suitable stream of sulphuric acid in an absorber and the withdrawn acid, containing absorbed oleiins, passed directly to the alkylation reactor where it is contacted with the isoparaflin stream, in the usual manner. So also thel product of the alkylation zone may be subjected to separation and the recovered acid recycled to the absorber in the usual manner.

It is important also to note that the present invention contemplates interexchange of recycle streams between the two reaction zones in such a manner as to permit additional adjustment of the respective total feeds. To this end, conduit 15 and pump 16 direct recycle stock from the line 14 to the inlet pipe I3 of reactor I4 as required. Conversely, valved branch pipe 11 permits recycle stock from line 23 to be controlledly supplied to reactor 5 I.

In accordance with a modified process shown in Figure 2, a primary reaction zone which may be the same .as above, is supplied with synthesis gas rthrough inlet pipe 8|, branch pipe 82 and pump 83, and the products of reaction pass, preferably at a lower pressure, through condenser 84 and separator 85. The liquid hydrocarbon layer passes by way of pipe 36 to stabilizer 81. Tail gas from the separator 85, subject to recycle of any portion and to venting through branch pipe 88, as desired for purposes of control, is passed directly through pipe into the inlet of the secondary reaction zone 9i, together with additional synthesis gas from inlet manifold Il.

Reaction products from the secondary reactor are thereafter condensed as at 92 and separated as at 03, the liquid oily layer passing by way of pipe 94 to the aforementioned pipe 06 and the stabilizer 81. Return line 95 permits recycle of any desired portion oi' the separated normally gaseous products of reaction to the reactor. Residuai tail gas from pipe 96 flows to a sepmation system of the character described above, comprising an absorber S1, in which a suitable liquid absorbent takes up C4 hydrocarbons, and is stripped ln tower 88. 'I'he oil gas from the absorber Si comprises any residual unreacted feed gas, inerts, light hydrocarbon gases and the like, and may be returned, if necessary, to control the feed to either or both of the reaction zones. The stripped gases pass through pipe 99 to a fractionation system operating to remove normal butane as at |0| and deliver a stream of isobutane and butylene through pipe |02 to the alkylation unit 42.

Stabilizer 81 delivers through outlet |05 a normally liquid stream which may be a motor gasoline product. It also delivers an overhead stream of C4 hydrocarbons thru pipe |06, to the alkylation plant as shown. Alternatively this stream may pass through valved branch line |01 to the inlet 89 of the fractionator |00.

As indicated diagrammatically, the normal butane in line I0| may be used to pressure the motor gasoline fractions which constitute or are includedl in the hydrocarbon stream oi.' pipe |05.

Moreover, it is important to note that any excess or desired portion of the normal butane in the pipe |0| may be conveyed by branch pipe |02 to the inlet line 82 of the isoparaln synthesis reactor l00. The stream of normal butane thus supplied to the reactor is isomerized within the reaction zone, by the isoparafiin synthesis catalyst, to form additional isobutane for alkylation. In addition, any substantial proportion of normal butane so added tends to suppress the overall formation of parailin hydrocarbons in this stage, thereby permitting the net production of normal butane to be held at a level approximating the actual requirements of the final motor gasoline. 'I'he embodiment of Figure 1 may be similarly modified.

The foregoing embodiment accordingly directs unaltered wet tail gas from the isoparailln synthesis step to the secondary reaction zone, subject to the controls indicated, whereby the contained isoparamns, carbon dioxide and hydrogen limit normal gaseous parailln production therein. and the carbon dioxide formed by the isoparailin synthesis step is consumed in increasing the yield of liquid hydrocarbons.

In accordance with one specific example, a synthesis gas containing essentially hydrogen and carbon monoxide in approximately the molar ratio of 1.5:1 is passed through a primary reaction zone containing uidized alumina-thoria catalyst, containing about alumina and about 80% thoria, at a pressure of about 300 atmospheres and a temperature of about 805 F. The

gasiform reaction products are removed from contact with the catalyst, reduced in pressure to about 200 pounds per square inch guage, and the stream condensed and separated at about '70 F. with the recovery of a liquid product essentially in the motor gasoline boiling range. C4 fractions are recovered from this gas, and the residue passed to a secondary reaction zone containing a uidized iron catalyst promoted with alumina and potassium oxide at a pressure of about 200 pounds per square inch gauge, and at a tempera- 8 ture of about 600 P. This stream is admixedf with additional fresh synthesis gas in the ratio of about one part of synthesis gas to two parts of tail gas from the primary reaction zone.

The withdrawn gasiform reaction products from the secondary reactor are similarly condensed and separated with the recovery of an additional stream of essentially motor gasoline fractions. The separated gases are recycled tothe secondary reaction zone at a recycle rate of about 2:1 on the basis of admixed synthesis gas. The unrecycled portion is treated for the recovery of C4 hydrocarbons and this stream, combined with the other C4 hydrocarbon stream is fractionated for the removal of normal butane and then supplied directly tosn alkylation system for the production of a high grade alkylate. f

The composition of the combined feed to the secondary reaction zone, excluding recycle, is substantially free of water vapor and contains hydrogen and carbon monoxide in the molar ratio substantially in excess of 3:1, and slightly under 4o moi percent of carbon dioxide on the basis of the total reactant content.

The carbon dioxide supplied to the secondary reaction zone is largely consumed in the production of additional liquid hydrocarbons.

-It is to be noted that the isoparamn synthesis reaction operates best at relatively low fresh feed ratios of hydrogen to carbon monoxide in the neighborhood of about 1:1 to about l.5:1, preferably about 1.2:1. On the other hand, the secondary reactor is most advantageously operated with a synthesis gas containing hydrogen and carbon monoxide in a ratio greater than about 2:1. As clearly shown above the present invention aii'ords an excess of hydrogen, typical of the ilrst reaction, to supplement the feed to the second reactor. thus permitting use of a common supply of synthesis gas which is relatively low in hydrogen. In short an overall ratio of less than about 2:1 in the fresh feed may be satisfactory.

0n the other hand, an HnCO ratio of 2:1 or greater in the fresh feed to the second reactor may result in better consumption of CO2, and the process is therefor even better controlled where separate feeds of synthesis gas are available, namely, a relatively low ratio of carbon monoxide to the first reactor and a higher one for the second.

While the isoparaiiin synthesis catalyst has been hitherto mentioned in terms of the aluminathoria, or the zinc oxide-alumina complexes, the

` mixtures of hydrocarbon synthesis catalysts with typical butane isomerization catalysts which are effective to isomerize butane under the pressure and temperature conditions at which the synthesis catalyst is also effective to synthesize hydrocarbons by the reduction of carbon monoxide with hydrogen; in short, where the synthesis catalyst effects hydrocarbon formation and the isomerizing catalyst effects concurrent isomerization to isoparafiins at the same temperature and pressure. 'I'he isomerizing catalysts Awhich may be employed in this connection are yeither synthetic or natural materials, such as diatomaceous earth, silica gel, magnesium silicates, aluminum silicates, activated alumina, bauxite, bentonite, and may others, and may be promoted with boron oxide, silicon oxide of hydrouoric acid. These may be eiective with catalysts such as thoria and zinc oxide referred to above. They are also effective as isomerization catalysts at synthesis temperatures below the temperature at whichA cracking proceeds at a substantial rate and within the range where hydrocarbon synthesis catalysts are effective to cause the reduction of carbon monoxide by hydrogen with the production of hydrocarbons. Therefor with such combinations, the hydrocarbon synthesis catalyst, may include typical catalysts such as cobalt, nickel, or

iron.

Obviously many modifications and variations of the invention as hereinbefore set'forth, may

be rmade without departing from the spirit `and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In the production of hydrocarbons of high antidetonation characteristics by the catalytic treatment of a synthesis gas comprising essentially hydrogen and carbon monoxide, the steps which comprise passing individual streams of said synthesis gas respectively through separate rst and second reaction zones, said rst reaction zone being maintained at a temperature in the range of about 750-900 F., and a pressure from about 50-500 atmospheres, and containing a metal oxide isoparaiiin synthesis catalyst effective under said reaction conditions to convert said reactants into predominantly isopraiilnc hydrocarbons with the formation of substantial quantities of by-product carbon dioxide, the second reaction zone being maintained at a temperature in the range of about 550-700 F., and an elevated pressure substantially below the range prevailing in the first reaction zone, and containing an iron type hydrocarbon synthesis catalyst effective under said reaction conditions to convert synthesis gas into predominantly olefnic hydrocarbons, effecting a substantial Vconversion of the synthesis gas fed to the rst reaction zone, withdrawing therefrom the eiliuent product stream, recovering from the withdrawn stream desired hydrocarbon fractions and included water Vapor, and injecting residual hydrogen and by-product carbon dioxide into the synthesis gas feed to the second reaction zone to form a gaseous feed mixture containing H2 and CO in a molar ratio above about 2:1, and a CO2 content suiiicient to direct. the water-gas shift reaction in that direction -which consumes CO2 and H2 to form a substantial quantity of additional CO at the temperature prevailing therein, effecting substantially complete conversion of CO in the second reaction zone into desired products of reaction and reacting isoparafllns from the eiiluent product stream of the first reaction zone with olens from the emuent product stream of the second reaction zone to form liquid alkylate.

2. The method according to claim 1 wherein said metal oxide isoparain synthesis catalyst comprises alumina and thoria.

3. The method according to claim 1 wherein said metal oxide isoparamn synthesis catalyst comprises zinc oxide and alumina.

4. The method according to claim 1 wherein the stream of synthesis gas supplied to the first 5 reaction zone contains Hz and CO in a molar ratio below about 2: l.

5. The method according to claim 1 wherein the stream of synthesis gas supplied to the first reaction zone contains H2 and CO in a molar ratio within the range of about 1:1 to about 1.5:l.

6. The method according to claim 1 wherein the streams of synthesis gas supplied to both the first and second reaction zones contain Hz and CO in amolar ratio below 2:1 and wherein the total feed to the second reaction zone, after injection of said residual hydrogen and by-product carbon dioxide, contains H2 and CO in a molar ratio substantially above 2:1.

7. The method according to claim l wherein normal paraiilnic hydrocarbons from the eiiluent products are recycled to the rst reaction zone to effect substantial isomerization thereof.

8. In the production of hydrocarbons of vhigh antidetonation characteristics, in the catalytic hydrogenation of carbon monoxide, the steps which comprise simultaneously passing individual streams of synthesis gas -comprising hydrogen and carbon monoxide in the molar ratio less than about 2: 1 through separate first and second reaction zones, said first reaction zone being maintained at a temperature in the range of about 750-900" F. and a pressure from about 50-500 atmospheres, and containing a metal oxide, isoparaffin synthesis catalyst effective under `such conditions to convert said reactants into an eiliuent product stream containing predominantly isoparafiinic hydrocarbons and substantial quantities of carbon dioxide and hydrogen, the second reaction zone being maintained in the range of about 550-700 F. and an elevated pressure, substantially below the range prevailing in the first reaction zone and containing an iron type hydrocarbon synthesis catalyst effective under said reaction conditions to convert the reactants into an eiiluent product stream containing predominantly oleflnic hydrocarbons, withdrawing the eiiiuent product stream from contact with the catalyst in the first reaction zone, recovering desired hydrocarbon fractions and included water vapor therefrom, and injecting residual hydrogen and byproduct carbon dioxide into the synthesis gas feed to the second reaction zone to form a gaseous feed mixture containing hydrogen and carbon monoxide in a molar ratio above about 2:1 and a carbon dioxidecontent suiiicient to direct the water-gas shift reaction in that direction which consumes carbon dioxide and hydrogen to form a substantial quantity of additional carbon monoxide at the temperature prevailing therein, effecting substantially complete conversion of carbon monoxide in the second reaction zone into said desired products of reaction, and reacting isobutane fractions from the hydrocar- 65 bon product of the first reaction zone with oleflns from the hydrocarbon product of the second reaction zone to form liquid alkylate.

9. In the production of hydrocarbons of high antidetonation characteristics by the catalytic 70 treatment of a synthesis gas comprising essentially hydrogen and carbon monoxide, the steps which comprise passing individual streams of said synthesis gas respectively through separate first and second reaction zones, said rst reaction zone 75 being maintained at a temperature in the range 1i of about '15o-900 F., and a pressure from about 50-500 atmospheres, and containing a. metal oxide, isoparanln synthesis catalyst effective under said reaction conditions to convert said reactants into predominantly isoparai'nic hydrocarbons with the formation of substantial quantities of by-product carbon dioxide, the second reaction zone being maintained at a temperature in the range of about 550700 F., and an elevated pressure substantially below the range prevailing in the first reaction zone, and containing an iron type hydrocarbon synthesis catalyst eiective under said reaction conditions to convert synthesis gas into predominantly oienic hydrocarbons, effecting a substantiel conversion of the synthesis gas fed to the irst reaction zone, withdrawing therefrom the eluent product stream,

recovering from the withdrawn stream desiredv hydrocarbon fractions and included water vapor, and inJecting residual hydrogen and by-product carbon dioinde into the synthesis gas feed to the second reaction zone to form a gaseous feed mix. ture containing m and CO in e. molar ratio above about 2:1, and a C0: content sumcient to direct the water-gas shift reaction in that direction which consumes CO: and Ha to form a substantial quantity of additional CO at the temperature pre- 12 veiling therein, effecting substantially complete conversion of CO in the second reaction sone into desired products of reaction and recovering desired hydrocarbons from the eiiluent product stream thereof.

.TALES H. GRAHAM.

REFERENCES GITE!) The following references are of recordin the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,798,288 Wietzei et ai Mar. 31, 1931 2,2%,048 Herbert Dec. 3, 1940 2,253,607 Boyd et al Aug. 26, 1941 2,257,074 Goldsby Sept. 23, 1941 2,257,293 Dreyfus Sept. 30, 1941` 2,286,814 Kemp June 16, 1942 2,347,682 l Gunness May 2, 1944 2,360,463; Arveson Oct. 17, 1944 2,417,164 `Huber Mar. 11, 1947 2,436,957 Eastman Mar. 2, 1948 OTHER RmERENCEs Article in The Oil and Gas Journal, of Jannary 19, 1946, pages 36 and 89. 

1. IN THE PRODUCTION OF HYDROCARBONS OF HIGH ANTIDETONATION CHARACTERISTICS BY THE CATALYTIC TREATMENT OF A SYNTHESIS GAS COMPRISING ESSENTIALLY HYDROGEN AND CARBON MONNOXIDE, THE STEPS WHICH COMPRISE PASSING INDIVIDUAL STREAMS OF SAID SYNTHESIS GAS RESPECTIVELY THROUGH SEPARATE FIRST AND SECOND REACTION ZONES, SAID FIRST REACTION ZONE BEING MAINTAINED AT A TEMPERATURE IN THE RANGE OF ABOUT 750-900*F., AND A PRESSURE FROM ABOUT 50-500 ATMOSPHERES, AND CONTAINING A METAL OXIDE ISOPARAFFIN SYNTHESIS CATALYST EFFECTIVE UNDER SAID REACTION CONDITIONS TO CONVERT SAID REACTIONS INTO PREDOMINANTLY ISOPRAFFINC HYDROCARBONS WITH THE FORMATION OF SUBSTANTIAL QUANTITIES OF BY-PRODUCT CARBON DIOXIDE, THE SECOND REACTION ZONE BEING MAINTAIN AT A TEMPERATURE IN THE RANGE OF ABOUT 550-700*F., AND AN ELEVATED PRESSURE SUBSTANTIALLY BELOW THE RANGE PREVAILING IN THE FIRST REACTION ZONE, AND CONTAINING AN IRON TYPE HYDROCARBON SYNTHESIS CATALYST EFFECTIVE UNDER SAID REATION CONDITIONS TO CONVERT SYNTHESIS GAS INTO PREDOMMINANTLY OLEFINIC HYDROCARBONS, EFFECTING A SUBSTANTIAL CONVERSION OF THE SYNTHESIS GAS FED TO THE FIRST REACTION ZONE, WITHDRAWING THEREFROM THE EFFLUENT PRODUCT STREAM, RECOVERING FROM THE WITHDRAWN STREAM DESIRED HYDDROCARBON FRACTIONS AND INCLUDED WATER VAPOR, AND INJECTING RESIDUAL HYDROGEN AD BY-PRODUCT CARBON DIOXIDE INTO THE SYNTHESIS GAS FEED TO THE SECOND REACTION ZONE TO FORM A GASEOUS FEED MIXTURE CONTAINIG H2 AND CO IN A MOLAR RATIO ABOVE ABOUT 2:1, AND A CO2 CONTENT SUFFICIENT TO DIRECT THE WATER-GAS SHIFT REACTION IN THAT DIRECTION WHICH CONSUMES CO2 AND H2 TO FORM A SUBSTANTIAL QUANTITY OF ADDITIONAL CO AT THE TEMPERATURE PREVAILING THEREIN, EFFECTS SUBSTANTIALLY COMPLETE CONVERSION OF CO IN THE SECOND REACTION ZONE INTO DESIRED PRODUCTS OF REACTION AND REACTING ISOPARAFFINS FROM THE EFFLUENT PRODUCT STREAM OF THE FIRST REACTION ZONE WITH OLEFINS FROM THE EFFLUENT PRODUCT STREAM OF THE SECOND REACTION ZONE TO FORM LIQUID ALKYLATE. 